* Added color utility functions: hex_to_rgba, rgba_to_hex, is_valid_hex with tests
* Parametrize hex and RGBA utility tests in `test_utils.py` for improved clarity and coverage
* Enhance hex and RGBA utilities: improve test coverage, validations, and docstrings; refactor shared logic.
* Refactor color input handling with `_normalize_color_input` utility; add hex string support across annotators and enhance test coverage
---------
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Jirka Borovec <6035284+Borda@users.noreply.github.com>
* refactor: reorganize project structure and update module imports
* configure setuptools to use 'src' layout and adjust package discovery
* refactor: move tests to `tests` directory and update imports accordingly
* update lint and mypy configurations to align with `src` and `tests` structure
* update test imports to use corrected `tests.helpers` module path
* fix(pre_commit): 🎨 auto format pre-commit hooks
Jirka Borovec
Soham Walam